[PATCH] knfsd: add some new fsid types

Add support for using a filesystem UUID to identify and export point in the
filehandle.

For NFSv2, this UUID is xor-ed down to 4 or 8 bytes so that it doesn't take up
too much room.  For NFSv3+, we use the full 16 bytes, and possibly also a
64bit inode number for exports beneath the root of a filesystem.

When generating an fsid to return in 'stat' information, use the UUID (hashed
down to size) if it is available and a small 'fsid' was not specifically
provided.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 80 insertions, 38 deletions

diff --git a/include/linux/nfsd/export.h b/include/linux/nfsd/export.h
index 045e38cdbe64..9f62d6182d32 100644
--- a/include/linux/nfsd/export.h
+++ b/include/linux/nfsd/export.h
@@ -74,19 +74,20 @@ struct svc_export {
         uid_t                   ex_anon_uid;
         gid_t                   ex_anon_gid;
         int                     ex_fsid;
+        unsigned char *         ex_uuid; /* 16 byte fsid */
         struct nfsd4_fs_locations ex_fslocs;
 };
 
 /* an "export key" (expkey) maps a filehandlefragement to an
- * svc_export for a given client.  There can be two per export, one
- * for type 0 (dev/ino), one for type 1 (fsid)
+ * svc_export for a given client.  There can be several per export,
+ * for the different fsid types.
  */
 struct svc_expkey {
         struct cache_head       h;
 
         struct auth_domain *    ek_client;
         int                     ek_fsidtype;
-        u32                     ek_fsid[3];
+        u32                     ek_fsid[6];
 
         struct vfsmount *       ek_mnt;
         struct dentry *         ek_dentry;
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index 4b7c4b568f6d..72feac581aa3 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/include/linux/nfsd/nfsd.h
@@ -254,18 +254,6 @@ void		nfsd_lockd_shutdown(void);
  */
 extern struct timeval   nfssvc_boot;
 
-static inline int is_fsid(struct svc_fh *fh, struct knfsd_fh *reffh)
-{
-        if (fh->fh_export->ex_flags & NFSEXP_FSID) {
-                struct vfsmount *mnt = fh->fh_export->ex_mnt;
-                if (!old_valid_dev(mnt->mnt_sb->s_dev) ||
-                    (reffh->fh_version == 1 && reffh->fh_fsid_type == 1))
-                        return 1;
-        }
-        return 0;
-}
-
-
 #ifdef CONFIG_NFSD_V4
 
 /* before processing a COMPOUND operation, we have to check that there
diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h
index d9c6c382165d..11e568ee0eeb 100644
--- a/include/linux/nfsd/nfsfh.h
+++ b/include/linux/nfsd/nfsfh.h
@@ -165,38 +165,91 @@ typedef struct svc_fh {
 
 } svc_fh;
 
-static inline void mk_fsid_v0(u32 *fsidv, dev_t dev, ino_t ino)
-{
-        fsidv[0] = htonl((MAJOR(dev)<<16) |
-                        MINOR(dev));
-        fsidv[1] = ino_t_to_u32(ino);
-}
+enum nfsd_fsid {
+        FSID_DEV = 0,
+        FSID_NUM,
+        FSID_MAJOR_MINOR,
+        FSID_ENCODE_DEV,
+        FSID_UUID4_INUM,
+        FSID_UUID8,
+        FSID_UUID16,
+        FSID_UUID16_INUM,
+};
 
-static inline void mk_fsid_v1(u32 *fsidv, u32 fsid)
-{
-        fsidv[0] = fsid;
-}
+enum fsid_source {
+        FSIDSOURCE_DEV,
+        FSIDSOURCE_FSID,
+        FSIDSOURCE_UUID,
+};
+extern enum fsid_source fsid_source(struct svc_fh *fhp);
 
-static inline void mk_fsid_v2(u32 *fsidv, dev_t dev, ino_t ino)
-{
-        fsidv[0] = htonl(MAJOR(dev));
-        fsidv[1] = htonl(MINOR(dev));
-        fsidv[2] = ino_t_to_u32(ino);
-}
 
-static inline void mk_fsid_v3(u32 *fsidv, dev_t dev, ino_t ino)
+/* This might look a little large to "inline" but in all calls except
+ * one, 'vers' is constant so moste of the function disappears.
+ */
+static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
+                           u32 fsid, unsigned char *uuid)
 {
-        fsidv[0] = new_encode_dev(dev);
-        fsidv[1] = ino_t_to_u32(ino);
+        u32 *up;
+        switch(vers) {
+        case FSID_DEV:
+                fsidv[0] = htonl((MAJOR(dev)<<16) |
+                                 MINOR(dev));
+                fsidv[1] = ino_t_to_u32(ino);
+                break;
+        case FSID_NUM:
+                fsidv[0] = fsid;
+                break;
+        case FSID_MAJOR_MINOR:
+                fsidv[0] = htonl(MAJOR(dev));
+                fsidv[1] = htonl(MINOR(dev));
+                fsidv[2] = ino_t_to_u32(ino);
+                break;
+
+        case FSID_ENCODE_DEV:
+                fsidv[0] = new_encode_dev(dev);
+                fsidv[1] = ino_t_to_u32(ino);
+                break;
+
+        case FSID_UUID4_INUM:
+                /* 4 byte fsid and inode number */
+                up = (u32*)uuid;
+                fsidv[0] = ino_t_to_u32(ino);
+                fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
+                break;
+
+        case FSID_UUID8:
+                /* 8 byte fsid  */
+                up = (u32*)uuid;
+                fsidv[0] = up[0] ^ up[2];
+                fsidv[1] = up[1] ^ up[3];
+                break;
+
+        case FSID_UUID16:
+                /* 16 byte fsid - NFSv3+ only */
+                memcpy(fsidv, uuid, 16);
+                break;
+
+        case FSID_UUID16_INUM:
+                /* 8 byte inode and 16 byte fsid */
+                *(u64*)fsidv = (u64)ino;
+                memcpy(fsidv+2, uuid, 16);
+                break;
+        default: BUG();
+        }
 }
 
 static inline int key_len(int type)
 {
         switch(type) {
-        case 0: return 8;
-        case 1: return 4;
-        case 2: return 12;
-        case 3: return 8;
+        case FSID_DEV:          return 8;
+        case FSID_NUM:          return 4;
+        case FSID_MAJOR_MINOR:  return 12;
+        case FSID_ENCODE_DEV:   return 8;
+        case FSID_UUID4_INUM:   return 8;
+        case FSID_UUID8:        return 8;
+        case FSID_UUID16:       return 16;
+        case FSID_UUID16_INUM:  return 24;
         default: return 0;
         }
 }